There are two main accounts which have been proposed to explain why young children fail a test of false belief: early competence and conceptual change. The early competence view was tested in five experiments. This view states that a child who fails the false belief test fails because of elements of the task which are unrelated to an understanding of false belief. The five experiments have investigated: the effect of increasing the salience of the protagonist’s mental state; having a deceptive motive; active participation; having the target item absent when the false belief question is asked (all Experiment one); the difference between implicit and explicit measures of performance (Experiment one); the influence of question order (Experiments two and three); nature and presence of the protagonist (Experiment two); the influence of the reality control question (Experiment three); correlations between inhibitory control and working memory with the false belief task (Experiment four); and knowledge inhibition (Experiment five). Results indicated that only knowledge inhibition played any real role in performance, with three-year-old participants performing significantly better on a task where they did not have to inhibit their own knowledge in order to pass the test question. Implications of this research with regard to use of the false belief task, and the foundations for future research are discussed.